I had two beers in a row have the same wild yeast infection. Starts off slightly fruity and peppery then progresses to gross over a few weeks. I've successfully brewed two more beers without any problem and I'm trying to figure out exactly what happened.

Both beers used the same hops for dry hops, from the same supplier. I knew I had a problem with the first beer when I brewed the second, so I was extra careful about cleaning and sanitizing.

Both beers are cloudy even after using Irish moss in the boil (and gelatin after kegging for the second one).

My latest two beers are both lagers and neither tastes off after 8 days fermenting.

So, is it at all possible that the hops was the source of the wild yeast?

What are some other sources? Is it as easy as wind blowing it into the kettle while I'm chilling? I keep a lid mostly on (doesn't fit perfectly with chiller in there).

For what it's worth these were my 24th and 25th batches and my first infection (if you don't count the maggots that one time )

I've done a ton of dry hopping and never had an infection I could attribute to to doing it. The alcohol that's already present in the beer and levels of hop acids present in hoppy beers make it much less likely than something like sub par sanitation (we've all been there at some point) or wind blowing into the kettle as you mentioned.

I had a beer go south after I dry hopped once a few years ago. It was the only time I ever had an issue that I am aware of that I could directly relate to the dry hops. Doesn't mean that is what it was for sure but the beer tasted great, then tasted awful after I dry hopped it. In fact, afterward it took my some time before I got the courage to go back to dry hopping.

Cloudy plus flavor change usually indicates an infection but I'd be more inclined to suspect bacterial infection if it stays cloudy. Most yeast strains will drop out after a few days. Even weizen yeast will eventually drop out. In my experience, wild yeast like to form small clumps. However, that doesn't mean it has to be bacterial.

The hops could be a source of infection but I'd look at your other processes for other opportunities for infection to occur.

I've since doubled down on sanitation. Plus I'm now tasting at every step including tasting my starters. I threw away the last two ounces of the hops I used but now I wish I had kept them and done an experiment. Oh well.

I've since doubled down on sanitation. Plus I'm now tasting at every step including tasting my starters. I threw away the last two ounces of the hops I used but now I wish I had kept them and done an experiment. Oh well.

Perhaps you need to ease up on all the tasting as the more times you pull samples and mess with the beer the more risks you run in contaminating the batch

I dry hop a lot of my beers and have never had an infection from it. I guess it's possible. Basically I put the wort in primary, pitch yeast, cover the bucket, add the blow off tube and leave it be for a minumum of 10 days before taking a reading and it's usually done, add the hops, sit for 5-7 days and then package. The primary is only opened twice.

Perhaps you need to ease up on all the tasting as the more times you pull samples and mess with the beer the more risks you run in contaminating the batch

I dry hop a lot of my beers and have never had an infection from it. I guess it's possible. Basically I put the wort in primary, pitch yeast, cover the bucket, add the blow off tube and leave it be for a minumum of 10 days before taking a reading and it's usually done, add the hops, sit for 5-7 days and then package. The primary is only opened twice.

I guess I should have clarified: whenever necessary to pull a sample (pre-ferment, post-ferment, decant starter) I'm now tasting it. I don't normally take samples mid-ferment for precisely this fear of contamination.

Perhaps you need to ease up on all the tasting as the more times you pull samples and mess with the beer the more risks you run in contaminating the batch

I dry hop a lot of my beers and have never had an infection from it. I guess it's possible. Basically I put the wort in primary, pitch yeast, cover the bucket, add the blow off tube and leave it be for a minumum of 10 days before taking a reading and it's usually done, add the hops, sit for 5-7 days and then package. The primary is only opened twice.

I guess I should have clarified: whenever necessary to pull a sample (pre-ferment, post-ferment, decant starter) I'm now tasting it. I don't normally take samples mid-ferment for precisely this fear of contamination.

What are some other sources? Is it as easy as wind blowing it into the kettle while I'm chilling? I keep a lid mostly on (doesn't fit perfectly with chiller in there).

One small thing you could do with regard to the chiller/lid open space is to seal with aluminum foil. Even if your kettle lid is notched, some foil is good to seal the gap. I StarSan spray a sheet and then conform it over the opening since I brew outdoors and subject to the elements.

That'll minimize both microscopic critters on the wind as well as bigger bugs getting in and getting lucky with your wort.